Unlocking Greatness with Black Keys
by Alavaria
Summary: Small stories, set in a (very) alternate Chaldea. The FATE system summons more than just Servants, and some of them might find Black Keys a useful weapon. More about the humor or just random "fits" for the (in)famous CE.
1. Chevalier d'Eon - Rapier and Dagger

**Chevalier d'Eon**

 **Rapier and Dagger**

* * *

The Heroic Spirit of the Sword (rapier) Chevalier d'Eon looked in confusion at the bluish hilt - and nothing else- that Chaldea's First Master had eagerly presented him with.

"Gudako, what exactly is this?" An educated guess said some sort of Mystic Code or other such tool, probably a weapon but he already had one.

"It's a Black Key," she replied immediately. "Or rather, it looks like one, but it's really the crystallization of the concept of 'a weapon that strikes swiftly, with deadly accuracy'. I think it'd suit you."

"Where would you even get something like this? Actually, how would I use it, I'm not a magus?" It felt heavy for a mere hilt of its size, but had no obvious markings to suggest how it was activated.

"You're a Servant, so channel some of your prana into it and fix in your mind what form you want." Doing so resulted in a long narrow thrusting blade. d'Eon frowned and knocked the tip against the wall next to him.

"Oh. I thought you'd want it more like a main-gauche," she commented, voice slightly tinged with disappointment. "Wasn't rapier and dagger the preferred form in your time?"

"Ah," he said, remembering. "Now that you mention it, I wonder why I wasn't summoned with this sword's partner."

As the Black Key's blade shrank to that of a long dagger, d'Eon transferred it to his left hand in order to draw his scabbarded weapon and take a fencing stance.

"Probably didn't have enough of a legend. Well let me know how it goes."

* * *

 **Notes**

 _Not a really serious series. It's not the same Chaldea as canon FGO, but anyway this is just focusing on Servants who might find use for Black Keys.  
_

 _Though they're CEs you equip (and look like a set of three) in these stories each "summon" is a single Black Key with slightly different concept of a weapon, corresponding to the trio of Quick (Verdant), Arts (Azure) and Buster (Crimson)._


	2. Tamamo Cat - Ultimate Kitchen Knife

**Tamamo Cat**

 **Ultimate Kitchen Knife**

* * *

Several of the Servants in Chaldea mentioned the culinary ability of a certain Tamamo-no-Mae they had served under in a faraway land known as .PH. Even the well-known cook, Tamamo Cat, admitted as such. Given how even heroic spirits found her skills commendable, that said quite a lot about "the original."

One of Cat's grouches was how the various knives forged by human were not ideal for her own hands (paws). It would be a challenge to find a set able to keep up with the cooking prowess of an enthusiastic heroic spirit of berserker rage.

Gudako looked about the kitchen for any filtchable foods. While other kitchen staff might mind such things, Cat actually hardly noticed or cared. It was odd how a being without self-restraint, self-control or general reason was able to command something as delicate as Chaldea's food needs, but she did so admirably.

"Yah~ Master, what can this Cat get for you?"

Gudako brushed aside Cat's sudden "revelation" that her Master really wanted to eat fried tofu right at that exact moment, before handing her what looked like a knife handle, less the blade.

"What's this, woof?"

"It is the ultimate kitchen knife!" Gudako proclaimed, causing some of the others nearby to look curiously at the amazing tool. "If you provide it with some prana and a good image of the blade you want, I am sure it will not disappoint!"

"Ooh~" the berserker quickly noted how the handle had been shaped to easily fit her paws before trying out the special function experimentally. A few different blade types later and the Servant was cheerfully chopping, slicing and paring while her knife morphed on the fly to fit each task.

"Wow," Gudako commented to no one in particular. Cat had forgotten everything else while pushing the limits of this newfound flexibility on her technique. "That could have some interesting applications."


	3. Jack the Ripper - Claw Style

**Jack the Ripper - Claw Style**

* * *

"You know, I've been wondering," Gudako asked a visiting Jack while they were on a minor singularity together. "You seem to carry a lot of knives with you, but you don't use more than two at a time?"

"How would that work? I tried but mommy said it was dangerous to run about with six knives," the assassin replied after a moment.

Gudako responded by pulling out six Black Keys. Three were of the Quick variety while the other set was of the Buster variety. Using one of each as a pair provided a serious challenge to the user, but even more to the opponent who might assume the weapons were identical because of their looks. She quickly grabbed all six in the fan formation that she had seen before.

"I was wondering ever since a Servant, Amakusa, did something like this. I was hoping a knife master like you might recognize the technique."

"Ooh, a claw style, like the famous Servant Wolfer***. But I don't know it."

"Damnit," Gudako frowned. She couldn't bring Jack back to Chaldea with her, and letting go of the relatively rare Black Keys and hoping to encounter her again was also not a great option. "What about we experiment? I know a person..."

* * *

(A few days later)

Cu Chulainn shouted when he saw the figure emerging out of the mists with six Black Keys in hand. It was probably a trauma from previous encounters with certain priests who liked using the weapon. Jack took this as a sign to action and sprung onto the attack.

Gudako nodded, taking mental notes as the impromptu sparring session turned experiment unfolded. The ability to modify each Key's blade on the fly was very useful in combat, even more than Cat's increasingly incomprehensible cooking techniques. A Servant with nimble fingers could also manipulate each Key with some degree of independence.

Annoyed by her inability to close though Cu's solid defense, Jack finally threw one of the Keys at him. However, the Lancer's Protection from Arrows totally no-sold that attack. But this reminded his Master of another knife master Servant with a similar attack.


	4. Ryougi Shiki - Mystic Poke of Death

**Ryougi Shiki**

 **Mystic Poke of Death**

* * *

"Just the knife user I was looking for," Gudako said upon finding Shiki on her way to get more ice cream. "Catch!"

Shiki easily snagged the pair of Black Keys thrown towards her (in hilt-only form). "What're these?" Gudako took a moment to explain how the weapons functioned.

"So," she said after Shiki had gotten the hang of modifying the blades on the fly. After seeing Cat switch while cutting, it occurred to me you can also extend the blade while cutting or thrusting in order to catch an opponent by surprise."

Shiki thought about it while trying out a few moves on the air in front of her. "Yes, but it would lack any real strength - I see why you were looking for me now."

"Yep!" As expected, the one who uses knives in such a special manner caught on quickly. "Since your _technique_ can penetrate or cut with minimal force, the flexibility of these might be great. As for practicing..."

The pair paused as Cu Chulainn turned the corner, looking for a good beer. He spotted Gudako, then Shiki, then the two Black Keys held by the latter. Silently he turned around and sprinted away.

"Oh, it must be his famous **Disengage** skill," Shiki commented. Gudako just grinned, understanding what the Lancer was up to. "Anyway, as I was saying, since you can't really test that safely in sparring, hold onto these two and also these two."

She handed over another pair. "Honestly, I don't think you really need the Quick ones, rather your knife work is more like an Art, which is really hard for enemies to deal with since you don't intend to target the usual points to kill them. To start off easy, maybe you could get some time on on the... **Hands of Dawn**!"

It was Shiki's turn to attempt to **Disengage**. She couldn't escape.


	5. Cursed Arm Hassan - Throwing Swords

**Cursed Arm Hassan**

 **Cursed Keys**

* * *

Gudako walked around Chaldea while juggling a half-a-dozen Black Keys. As each one touched her hand, it received a small charge of magical energy, allowing the blades to flicker faintly as the weapons flew in the air.

"Oh, there you are, Arm." She spotted her target, the distinctive Cursed Arm Hassan. "Catch!"

Quickly whipping out more of the hilts, she threw them at the Assassin, who effortlessly snagged them out of the air. He glanced at the reddish items, unsure of their ultimate purpose.

"Shiki didn't want these ones," his Master explained. "They hit really hard but, well you know her style..."

"I see," he replied while fiddling carefully with one. She quickly showed him how they operated. "Yes, I do enjoy throwing knives, but specialized throwing swords?"

"Apparently the Church people employ them primarily for throwing. These should provide an interesting challenge for any enemy, combined with your style and usual weapons."

"I'll give it a try. Though a true comparison would need some serious targets to go all-out on," he said politely, while waving a Key about to get used to the balance.

"You can have your pick of mundane dragons, or phantasmal swallows."

"What?"'

* * *

 _l_

* * *

 _Notes:_

 _Kuro is here, but Emiya (and various versions) are not. Child-Gil is but he's special. I'm not sure if there are other Servants who throw swords._

 _Scathach throws multiple of her Gae Bolgs, but she isn't present either._


End file.
